1. Field of the Invention
This invention relates to medical devices. Specifically, the present invention relates to accurate positioning of a medical device.
2. Description of Related Art
During many medical procedures, a medical device is inserted into the patient's body. The medical device is then used to excise, medicate, or otherwise treat, for example, a region, tumor, or other structure within the patient's body. During such a procedure, the medical device is obviously hidden from the view of the medical practitioner. Thus, it can be difficult for the practitioner to know the precise location of the medical device with respect to the region of interest within the patient's body.
With reference now to Prior Art FIG. 1, a schematic cut-away of an artery 100 having a catheter 102 inserted therein is shown. In Prior Art FIG. 1, a tumor 104 is shown located on the right side of artery 100. Many internally-used medical devices, such as catheter 102, have rotational differences. That is, catheter 102 directs a treatment such as, for example, chemotherapy agents, via opening 105 in the side of catheter 102. Hence, when disposed as shown in Prior Art FIG. 1, the chemotherapy agents would be emitted in the direction of arrow 106, instead of towards tumor 104. Thus, in many medical procedures, the medical practitioner needs to know the rotational orientation of the medical device within the patient's body.
In many conventional approaches, the medical practitioner uses a rotational gauge to roughly determine the rotational orientation of the medical device. Such a gauge is typically attached to the medical device at a point where the medical device extends out of the patient's body. However, such rotational gauges only provide a rough estimate of the rotational orientation of the medical device. That is, due to the circuitous path that the medical device may follow within the patient's body, it is very difficult for the medical practitioner to know the precise rotational orientation of the end of the medical device.
In Prior Art FIG. 2, a conventional location determination approach is shown. In the approach of Prior Art FIG. 2, a radiographic element 108 is attached to the end of catheter 102. During the medical procedure, x-rays are used to locate the position of the end of catheter 102 within the patient's body. Although such an approach determines the position of the end of the medical device within the patient's body, such an approach does not determine the rotational orientation of the medical device within the patient's body. Thus, as shown in Prior Art FIG. 2, even though the position of the end of the catheter is known and is located as desired, the rotational orientation of catheter 102 is not as it should be.
Additionally, in some medical procedures it may be necessary to know the azimuthal orientation of the medical device within the patient's body. At present there is no practical method for accurately determining the rotational and/or the azimuthal orientation of the medical device within the patient's body.
Thus, a need exists for a method and apparatus for accurately determining the orientation of a device with respect to an x-ray source.